The present invention relates to signalling means for a vehicle of a kind related to the type of signalling means indicating that a vehicle is braking.
Brake lights on a vehicle are illuminated when the brakes of the vehicle are applied, the purpose being to indicate to vehicles following that vehicle that it is slowing down or stopping.
A significant number of accidents are caused when one vehicle runs into the back of another vehicle, and whereas brake lights present on existing vehicles give an indication to a person following that the vehicle in front is braking, it would be advantageous if some earlier warning of slowing down or braking of the vehicle could be provided.
It has been proposed to provide signalling means that will operate on de-acceleration of the vehicle. However, even though many proposals have been made for such devices, they have not been found to he practical, primarily because vehicles in their normal running are continually accelerating and de-accelerating, thus de-acceleration activated signalling means will excessively be operated causing distraction to drivers behind and, because they will often be activated, irrespective of the fact that a xe2x80x9cno hazardxe2x80x9d situation has arisen, they will tend to be ignored by following drivers, thus causing more confusion than benefit.
It is an object of the present invention to provide new or improved signalling means suitable for use on a motor vehicle.
According to one aspect of the present invention I provide signalling means adapted for use on a vehicle, said signalling means being activated in response to a signal from a sensing means, said sensing means being adapted to sense the movement of the brake operating part of the driver in a direction likely to result in the brakes associated with that vehicle being applied.
Such movement may comprise movement of the foot of the person driving the vehicle from the accelerator and/or may comprise movement of the foot of the driver of the vehicle in a direction from the accelerator towards the brake pedal.
In one form said sensing means may comprise a switch on or near the accelerator that will change condition when the driver""s foot is partially or totally removed from the accelerator.
The switch may be pressure sensitive, a contact switch or a proximity switch.
The sensing means may be adapted to sense movement of the driver""s foot to a position at which the foot is partly over the brake pedal.
Preferably the sensing means comprise detectors that are capable of sensing movement of the driver""s foot, and conveniently may comprise a radiation emission and receiving device, the arrangement being such that the emission device emits radiation which is reflected by the foot of the driver of the vehicle and received by the receiving device. With such an arrangement it may be possible to detect not only movement of the foot but the position of the foot relative to the accelerator pedal of the vehicle and/or the brake pedal, and/or indeed the speed of movement of the foot.
The foot sensing means may be connected to a control circuit which receives input signals from other sensing means associated with the vehicle. Such input signals may comprise a signal indicating the speed of the vehicle, whether or not the vehicle is stationary, and may include further sensing means such as following vehicle detecting means.
Vehicle detecting means may cause the signalling means to operate should a following vehicle come within a specific distance. The specific distance may depend on the speed at which the vehicle is travelling.
It is further envisaged that time delays may be built into the control circuit so that when the device is operated it will not be de-activated until a certain time has elapsed and/or vehicle monitoring means are indicative that the signalling means may be de-activated. Such a provision will prevent constant activation and de-activation of the signalling means, such as in a congested or slow moving traffic situation.
Preferably the sensing means comprise ultrasonic detectors which are capable of detecting not only the position of the foot of the driver but also the rate of movement of the foot.
Thus, the signalling means may only be activated if the rate of movement exceeds a certain threshold.
The sensed movement may comprise a single foot movement or a sequence of movements including movement of the foot of the driver of the vehicle in a direction from the accelerator pedal towards the brake pedal to provide discrimination against other foot movements which may not be in response to a perceived need to apply brakes and which could give rise to false signals.
Preferably a sequence of foot movements is sensed which can be associated with a high probability of application of the brakes.
The signalling means may be activated when the sequence has been completed and may be activated only when the vehicle ignition switch is on and a predetermined sequence of foot movements has been completed. The signalling device may remain activated until the foot of the driver is again returned to the accelerator pedal or the engine is switched off. Such a sequence will minimise the possibility of false alarms which is one of the primary aims of the system and provides a significant advantage over previous proposals.
In a further implementation the velocity of movement of the foot of the driver during its removal from the accelerator pedal and/or movement towards the brake pedal at more than a predetermined rate may signal to drivers of following vehicles that a hazardous situation has been recognised by the driver. In such a situation the signalling means could be the existing hazard warning lamps.
It is further envisaged that the control circuit may also receive input signals from other sensing means associated with the vehicle.
Preferably the signalling means comprises a light-emitting source on the rear of the vehicle and, conveniently, may comprise a high mounted stop lamp of the kind which is now fitted at the rear of most new vehicles.
Alternatively, an additional light source or sources may be provided or another indicating means may be provided which may be illuminated so as to be clearly visible by the driver of a following vehicle, but without itself providing an active light source.
According to a further aspect of the present invention I provide a method of indicating the likelihood of imminent de-acceleration of a vehicle comprising the step of sensing movement of that part of the driver that operates the brakes associated with the vehicle in a direction towards a braking movement.
Preferably the control circuit associated with the signalling means is such that the movement of the part of the driver operative to operate the brakes may be sensed for a period of time so that the travel path of said part of the driver and the speed of said part that is likely to lead to the brakes being applied to the vehicle, can be detected and analysed and the control circuit supplied with such information so that the signalling means operates only when an imminent braking situation is detected to avoid spurious signals being emitted.
The device and method of the present invention provide significant advances over previous devices and recognise that it is the driver of the vehicle who is controlling operation of the vehicle so that analysing movement of the relevant parts of the driver of the vehicle, is more likely to give a clear indication of imminent braking than any measurement associated with the vehicle itself. It is necessary for the driver to react first before the vehicle can respond.
Furthermore, by sensing movement of the relevant parts of the driver of the vehicle and causing activation of the signalling means only when imminent braking of the vehicle is likely, misleading signals are prevented or at least reduced. By the possible incorporation of time delays and inputs from other vehicle sensing means such as the speed of the vehicle, a reliable indication may be given to following drivers of imminent braking of a vehicle in front which may enable the driver of a following vehicle to receive a valuable advance warning of a hazardous situation.